Synchronization system and method

• US 8,385,491 B2
• Filed: 04/29/2005
• Issued: 02/26/2013
• Est. Priority Date: 03/17/2004
• Status: Expired due to Fees

• Current Assignee: Hadad, Zion
• Original Assignee: Hadad, Zion
• Inventors: Hadad, Zion
• Primary Examiner(s): Corrielus, Jean B
• Application Number:
  US11/117,411
• Publication Number:
  US 20050207446A1
• Time in Patent Office: 2,860 Days
• Field of Search: 375/342, 375354-355, 375/359, 375/368
• US Class Current: 375/354
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

In a system packing multiple PDUs on a single physical burst and using OFDM or OFDMA, a synchronization method comprising: a. performing an initial lock; b. processing each new header information, verifying if checksum OK, and if OK—remain in (b), system is in locked state; c. activating new header seeker, to enable running window processor to compare the expected checksum with the last byte as tentative checksum; d. declaring Tentative lock, when detecting a checksum correspondence; e. declaring Final lock, when two or more consecutive successful detections of headers, at their expected locations based on prior detections, then Goto (b).

Claims

1. In a system packing multiple medium access control protocol data units (MAC PDUs) on a single physical burst and using orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency-division multiple access (OFDMA), a synchronization method comprising:

in a running window comprising a group of consecutively received bytes,

performing a synchronization by shifting bytes of said group of bytes into the running window,

continuously scanning the group of bytes, byte by byte, wherein for each byte, assuming that said byte is the beginning of a MAC PDU header, then verifying that said byte is the beginning of a MAC PDU header by calculating the header checksum on said byte and four bytes following said byte, and comparing the result to the value of a sixth byte following said five bytes and wherein, if the byte in question is indeed the beginning of a new MAC PDU header, then the calculated checksum value on the first five bytes will equal the value in the sixth byte, and synchronization of the physical burst is declared and declaring there is a large likelihood that the bytes form a valid MAC PDU header.

2. In a system packing multiple medium access control protocol data units (MAC PDUs) on a single physical burst and using orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency-division multiple access (OFDMA), a synchronization method comprising:

performing a synchronization by shifting consecutively received bytes into a running window,

continuously scanning the bytes in the order received, wherein for each byte, determining if said byte is the beginning of a MAC PDU header by calculating a header checksum on said byte and the four bytes following said byte, and, determining the occurrence of synchronization of a valid MAC PDU header if the calculated header checksum value on the first five bytes is equal to the value in the sixth byte;

verifying synchronization of the valid MAC PDU header by examining the received bytes for a subsequent MAC PDU header.

3. The synchronization method according to claim 2, wherein, if the subsequent MAC PDU header is found to be invalid, then concluding a false synchronization, and continuing to examine the bytes to determine synchronization.

4. In a system packing multiple medium access control protocol data units (MAC PDUs) on a single physical burst and using orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency-division multiple access (OFDMA), a synchronization method comprising:

performing a synchronization by shifting consecutively received bytes into a running window,

continuously scanning the bytes in the order received, wherein for each byte, determining if said byte is the beginning of a MAC PDU header by calculating a header checksum on said byte and the four bytes following said byte, and, wherein recognizing a MAC PDU header is done based on the fact that each MAC PDU header includes a header checksum field, determining the occurrence of synchronization of a valid MAC PDU header if the calculated header checksum value on the first five bytes is equal to the value in the sixth byte.